5 To help the pump prime faster and get oil flowing to the engine more quickly, apply a liberal amount of grease to the rotors. We’re using Joe Gibbs Driven assembly grease because it’s super sticky and stays in place. It also melts completely in engine oil and won’t affect performance once the engine is broken in. We’ve also seen engine builders pack this cavity with lighter weight lithium grease. If you do this, make sure to change the oil after the rebuilt engine has been broken in.